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don mouth naturalization and port lands flood protection

A New Mouth of the Don River, a new Community for Toronto

Toronto ranks as one of the most successful city regions in the world, with people from around the globe flocking to the downtown core for economic opportunities. In fact, roughly 120,000 new residents choose Toronto as their new home every year, all of whom are looking for a high quality of life. They want to live and work downtown with access to jobs, cultural amenities, parks and recreation areas and restaurants.

So when you think of where our downtown can grow – the remaining central areas where we can build new communities – this makes the waterfront something of a last frontier.

It is the last piece of significant land in the downtown area that can accommodate new communities and the single biggest opportunity on the waterfront is the Port Lands.

At about 356 hectares (880 acres) this extensive, underutilized area on Toronto’s eastern waterfront presents an unprecedented opportunity for redevelopment. Very few developed cities have the opportunity to revitalize such a massive brownfield site into new communities on prime waterfront land.

However, about 290 hectares (715 acres) of the area are currently at risk of flooding from the Don River watershed, meaning flood protection is required before any redevelopment can occur. The solution to this challenge is to naturalize the mouth of the Don River to provide the necessary flood protection and to unlock the development potential of this premier waterfront area.

Naturalizing the mouth of the Don River and providing flood protection for the Port Lands were identified as top priorities by all three orders of government when they first established Waterfront Toronto in 2001.

what will the naturalized river mouth look like?


A new mouth for the Don River will be created by excavating a new channel in the middle of the Port Lands between the Ship Channel and the Keating Channel, as well as a green spillway to help accommodate any overflow. The Project will result in  two new outlets for the river into Lake Ontario, new parks and green space along the river and inner harbour, continuous riverfront open space and expanded opportunities for people to experience the water’s edge. It will also enhance habitat for natural species and will re-establish wetlands in the area, which provide social and environmental benefits and naturally moderate the effects of flooding and erosion.


A new urban island - Villiers Island - will be emerge when the new mouth of the Don River is built. Villiers Island will act as a gateway from the West Don Lands and East Bayfront neighbourhoods into the rest of the Port Lands.

the benefits

The new, naturalized mouth of the Don River will transform the existing river mouth into the centrepiece of a series of new mixed-use waterfront communities, while delivering a healthier, more natural river outlet to the Toronto Inner Harbour and Lake Ontario. This transformational project will create an iconic identity for the lower Don River that will literally change the face of Toronto’s eastern waterfront.

The Don Mouth Naturalization and Flood Protection Project (DMNP EA) and Lower Don Lands Master Plan EA provide the blueprints for this bold and unprecedented project. This comprehensive solution addresses a complex set of problems by innovatively integrating ecology, development, transportation infrastructure, and the river mouth in a harmonious whole to deliver an extensive range of benefits.

Flood protecting the area enables the development of new, highly-livable, mixed-use communities, while maintaining the vital functions of Toronto’s only working port. With flood protection in place, a revitalized Port Lands will attract billions of dollars of private sector investment, provide capacity for the growing number of people who come to Toronto for the city’s economic opportunities, quality of life and vibrant cultural offerings, and support the city’s competitiveness among the top tier of global cities.

don mouth naturalization and flood protection project: how we got here…

The DMNP EA is an opportunity to alleviate the flood risk to over 290 hectares of land and more than 850 buildings south and east of the Don Mouth. By alleviating the flood risk to the area, land use restrictions can be removed, allowing revitalization of this prime waterfront location to proceed.

Planning for this work moved a significant step forward in 2006, when Toronto and Region Conservation (TRCA), in partnership with Waterfront Toronto and the City of Toronto, received approval for the Environmental Assessment Terms of Reference for the DMNP EA from the Ontario Ministry of Environment. The Terms of Reference set the parameters for the work that has been underway since.

Following approval of the Terms of Reference, four alternative solutions were developed to address the significant challenges within the Project Study Area, as identified in the EA. Because of the complex problems and significant technical challenges that needed to be addressed by the EA, Waterfront Toronto with the support of TRCA and the City of Toronto, held an International Design Competition in 2007 in recognition of the link between naturalization, flood protection, infrastructure and the land use potential of the area and the desire to find an integrated solution.

The competition’s stated goal was to obtain a bold and comprehensive concept design and a unifying vision to guide revitalization of the Lower Don Lands, merge the natural and urban fabric and establish an iconic identity for the Don River that accommodates crucial flood protection and habitat restoration. The competition also included a series of required design elements asking submissions to:

  • naturalize the mouth of the Don River,
  • create a continuous riverfront park system,
  • provide for harmonious new development,
  • extend Queens Quay eastward and enhance the road network,
  • prioritize public transit,
  • develop a gateway into the Port Lands,
  • soften existing infrastructure,
  • enhance the Martin Goodman Trail,
  • expand opportunities for interaction with the water, and
  • promote sustainable development.

In May 2007, Waterfront Toronto selected the Michael Van Valkenburgh Associates Inc. (MVVA) team as the winners of the Design Competition. Despite the large scale of the project, MVVA created a spectacular plan that addressed the myriad challenges posed by the site and the assignment.

MVVA's Port Lands Estuary Plan submission included a number of key elements that made it the clear winner. The concept relocated the naturalized portion of the river valley, included an overflow green spillway, and retained the Keating Channel as an urban artifact and third river outlet. MVVA’s concept also resolved the majority of the infrastructure challenges the team and the DMNP EA were struggling to resolve.

choosing MVVA's Port Lands Estuary Plan resulted in changes to the don mouth naturalization and port lands flood protection environmental assessment:

  • It expanded the study area under consideration
  • It created a new alternative for consideration and evaluation against the original four alternatives; and
  • It created a unifying vision to integrate the naturalized Don Mouth with the surrounding community, while addressing infrastructure needs and design.

In March 2008, the new alternative solution that was developed based on MVVA's winning concept was selected as the Preliminary Preferred Alternative. By January 2010, MVVA's concept had been refined and had undergone a detailed, formal evaluation and was chosen as the Preferred Alternative. The DMNP EA, with the new Preferred Alternative was submitted for Ministry of Environment approvals in December 2010.

The current plan has evolved over time, and while it is still based on MVVA’s award winning “Port Lands Estuary” plan, the original concept design has been modified several times through the DMNP EA process to meet project needs:

  • In 2008, for evaluation against the four original alternatives
  • In 2010, it was refined as part of the Preferred Alternative effects assessment process
  • In 2011/2012, it was refined through the Port Lands Acceleration Initiative, and
  • Has been further refined through the DMNP EA Amendment Process in 2013-2014.

The Don Mouth Naturalization and Port Lands Flood Protection Project Environmental Assessment received approval by the Minister of Environment and Climate Change on January 28, 2015. To view the Notice of Approval please visit the Ministry’s website here.

the port lands estuary plan (2007)

MVVA’s Port Lands Estuary Plan organized and prioritized the competition brief’s long list of required design elements using three broad categories: park, city, and river. Through these lenses, the team was able to communicate the project goals and design concepts of a diverse range of stakeholders, finding areas of overlap between the project’s wide-ranging aims.

Instead of creating naturalized banks along the straight course of the Keating Channel connecting the Don River with the lake, the Port Lands Estuary plan kept the channel as an urban artifact and neighbourhood amenity and created a new mouth for the river that flows logically from the upstream source, bypassing the abrupt right turn created by the channel, offering a large new meandering riverfront park that becomes the centerpiece of a series of new mixed-use neighbourhoods.

By taking an integrated approach to the project’s complex requirements, the team was able to use the naturalization of the mouth of the Don River as a vehicle to solve seemingly disparate issues of infrastructure, flood control, and neighborhood identity. The new river functions as both an ecological and infrastructure feature: it accommodates a narrow, shallow bed during normal flow, supporting water quality and wetland habitat and is designed to also serve as a large floodway during storm events.

The relocation of the mouth of the Don River makes it highly visible from other points around the Toronto Harbour, reasserting the river’s lost presence in the city and creating a highly desirable setting for new urban development.

The project will act as a catalyst for redevelopment of the underutilized Port Lands, replacing neglected post-industrial land with a bold and harmonious blending of neighbourhoods, infrastructure, and parks and open spaces that frame the new mouth of the Lower Don River.


don mouth naturalization becomes a reality

In June 2017, we announced $1.25 billion in tri-government funding for Waterfront Toronto to naturalize the mouth of the Don River, provide flood protection and lay the groundwork for new communities. This project, officially called Port Lands Flood Protection and Enabling Infrastructure (PLFPEI), will be a vital part of helping Toronto grow in a sustainable way. This $1.25 billion includes the $65-million in tri-government funding announced in September 2016 for Cherry Street Stormwater and Lakefilling (CSLF), a component of the larger PLFPEI. 

So, what happens now?

Port Lands Flood Protection and Enabling Infrastructure is comprised of 21 components and will take seven years to build. The plan is already in place and vetted through a rigorous due diligence process. That means we’re positioned to start detailed design right away. Because we received some funding for CSLF already, detailed design for CSLF started in September 2016 and is almost complete, with construction slated to begin this fall. 

Learn more about Construction on the Cherry Street Stormwater and Lakefilling Project in our recent blog post here.

related news

project status

Approved Budget:

quick facts

DMNP EA Study Area boundaries: Eastern Avenue in the north, Ship Channel in the south, Inner Harbour in the west, and Don Roadway in the east

Proximity: 20 minute walk to downtown

What the naturalization of the mouth of the Don River will deliver:


  • Over 1,000 m of new river channel
  • 13 hectares of new coastal wetland, with a 2 hectare wetland patch adjacent to the Don Roadway connecting to the Ship Channel.
  • 5 hectares of terrestrial habitat located within the constructed valley system with additional greenspaces anticipated outside the valley system
  • Creation and enhancement of 14 hectares of aquatic habitat

Flood protection facts:


  • 290 hectares of land are at risk due to flooding from the Don River, under a Hurricane Hazel-sized storm event
  • The new Mouth of the Don River will remove the flood risk to 240 hectares of land. The majority of the remaining 50 hectares of land still at risk due to flooding are designed to be flooded as they are located within the Keating Channel and the new naturalized river valley system. The Don Valley Parkway will continue to flood north of Lake Shore Blvd to Eastern Avenue. The only solution to flooding of the DVP would be to rebuild this section of the highway, which is outside the project scope.

Design Teams:


related events

February 22, 2018
Community Consultation: Don Mouth Naturalization and Port Lands Flood Protection


November 18 , 2015
Public Workshop - Connecting the Port Lands and South of Eastern Areas


November 17 , 2015
Public Workshop - Placemaking in the Port Lands


November 14 , 2015
Port Lands Public Open House and Information Sessions




the don of a new community

Take a tour of Toronto's Lower Don Lands

To the Waterfront

Watch to learn more about the revitalization of Toronto’s waterfront

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